Welcome again to our monthly newsletter with features on exciting celestial events, product reviews, tips & tricks, and a monthly sky calendar. We hope you enjoy it! 

• Starhopping 101
  Geoff Gaherty's guide to finding interesting objects in the sky if you don’t have (or don't want to use) computer assistance.
     
• Constellation in Focus: Aquarius
  Tricky targets this month: two planetary nebulas, three star clusters, and one of the sky's best double-stars.

In the August issue I wrote about exploring the sky using the Orion IntelliScope’s tour feature. But most telescopes aren’t equipped with computerized tours to guide the beginner through the sky. Here is a guide to finding interesting objects in the sky if you don’t have computer assistance.

Seeing versus finding

There’s difference between finding the location of an object and actually seeing it. Many of the objects we amateur astronomers look at are too faint to be seen with the naked eye. Some are too faint to be visible in our scope’s finder. Some may be so faint as to be a challenge to see in the main telescope. Seeing can be difficult. Finding an object, on the other hand, involves pointing the telescope at exactly the spot in the sky where the object is located. This can be done with a computer, or manually using a technique called starhopping. It’s not necessary to be able to see an object to point at it with the telescope.

Many beginners make the mistake of looking for objects which are easy to find (because they are close to bright stars or familiar constellations) but which are very hard to see, because they are very faint. For example, many go hunting for the galaxy Messier 101 in Ursa Major because it is located close to two bright stars in the handle of the Big Dipper. Unfortunately, M101 is one of the most difficult objects in Messier’s catalog to see because it is large in size and very faint, so its dim light is spread over a large area. Unless you have very dark skies and a trained eye, you can be staring right at M101 and never see it! So it’s important, when you’re starting out, to go for objects which are both easy to find (located near bright stars or constellations) and also easy to see (bright clear objects, such as double stars and star clusters). Leave the dim galaxies (for the most part) until you have more experience.

Starhopping

Starhopping involves pointing your telescope using known guideposts in the sky: bright stars and constellations. This in turn requires some familiarity with the stars and their grouping. When you first look up into a starry sky, especially from a dark rural site, the view can be overwhelming. You wonder, “How will I ever be able to make sense of all these stars?” Learning your way around the starry sky is very much like learning your way around an unfamiliar city. It helps to have a map. It helps to have a familiar landmark or two to get your bearings. And it also helps to have a friend to show you the way. For a map, you have software programs like Starry Night® which will give you an overview of the territory. You may know a few “landmarks” in the sky to get you going, such as the Big Dipper, Orion, a bright planet, or the Moon. An astronomical friend is also very helpful in the early stages, someone who knows the stars a bit better than you do and can point out some landmarks. You may know such a person already, or you may need to find one by joining a local astronomy club. Although I’m not out there under the stars with you, I hope some of my suggestions here will also help you get started.

The first step is to print out a chart or two to take outside with you. Many of the charts you find in books or magazines are less than helpful for two reasons: they try to show all the sky, and they show it on too small a scale. I prefer to use charts which show only part of the sky, but which are on a large enough scale to approximate the actual spacing of the stars across the sky.

For example, here’s a chart from Starry Night® showing a section of sky roughly 90 degrees square, facing east at 8 pm on November 5:

Go out with this chart and face east. The top of the chart is overhead, the bottom is the horizon. The most obvious object in the eastern sky is Mars, glowing brightly about a third of the way from horizon to overhead. But our targets for tonight are farther away. As I said earlier, the Big Dipper is a poor starting place for deep sky hunting because it lacks bright objects. Let’s look instead at Cassiopeia, a constellation which lies almost directly opposite the Big Dipper in the northern sky. In this chart, it's about two thirds of the way from horizon to zenith, an obvious lopsided W shape, visible even under city skies. Once you’ve identified Cassiopeia, you have some landmarks which will let you point your telescope at a variety of interesting objects.

Here’s a more detailed chart of the Cassiopeia, made by zooming in with Starry Night®:

Besides your star chart, you will need a red flashlight to read it. You will also find it very helpful to have a pair of binoculars with a field of view similar to that of the finder scope on your telescope. I find 10x50 binoculars particularly useful for this. Binoculars let you practise the “hop” in a more natural way than the view through the telescope’s finder, which is usually upside down. After I’ve tried a “hop” a few times with binoculars, I’m ready to repeat it with the telescope finder.

Two double stars

Let’s start by tracking down a couple of double stars. Many beginners are unaware that many of the stars which appear single to our naked eyes are double or multiple in a telescope. They are great targets for beginners because they are easy to see as well as easy to locate.

The five bright stars in Cassiopeia which mark the W are named, from top to bottom in this view: Beta β, Alpha α, Gamma γ, Delta δ, and Epsilon ε. We can find our first double star, Eta η Cassiopeiae, by looking a little less than half way between stars Alpha α and Gamma γ. You can see it there in the chart below, marked by the Greek letter Eta η. Place the crosshairs in the finder of your telescope on that star, and when you look through the telescope you will see it is actually two stars: a bright yellow one and a fainter red one.

The second double star is a bit farther afield, but illustrates the principles of starhopping. Look at the two top stars of the W, Beta β and Alpha α. Use the distance between these two stars as your “measuring stick.” Extend the line from Beta to Alpha by two stick lengths to the lower right, which will take you to the star 51 Andromedae. Continue in the same direction about half the distance again, and you will reach a brighter star, Gamma γ Andromedae. This is our target: in the telescope it will appear as a double star, the two stars a bit closer than Eta η Cassiopeiae, and this time colored gold and blue.

Four star clusters

Now let's go after some deeper targets, some of the beautiful star clusters located in or near Cassiopeia. First take a close look at Delta δ Cassiopeia (second from the bottom in the W). In binoculars you will see a fairly bright star below and to the right of it, Chi χ Cassiopeiae. Use the line between Delta and Chi as the base of an equilateral triangle hanging below them, and put the crosshairs of the finder on the lower angle of this triangle. Through the telescope’s eyepiece you will see a compact little star cluster, number 103 in Messier’s catalog. Imagine a tall thin isosceles triangle on the opposite side of the same baseline, put your crosshairs there, and through the telescope you will see the star cluster NGC 457. It has two bright stars in it which many people see as eyes. Traditionally those are the eyes of an owl, the rest of the cluster forming the erect body of the owl with wings outstretched. But to our modern eyes, it looks rather like the character E.T. in the famous movie. So this cluster is called by some the Owl Cluster and by others the E.T. Cluster!

Let’s go hunting farther away. This time use the line joining Gamma and Delta Cassiopeia as your measuring stick and pointer. Go twice its length downward towards the horizon and you should see a fuzzy patch through your binoculars and finder. Through the telescope you will see the Double Cluster in Perseus, one of the wonders of the night sky in any telescope. If you keep going in the same direction towards the horizon you will encounter a line of three bright stars, the last of which is at the center of a little known star cluster, Melotte 20. The trouble with this cluster is that it is so close to us that its stars are spread wide across the sky, too wide to fit in most telescopes, so that they can only be viewed with binoculars or the naked eye. This is one of the star clusters closest to our Sun, also called the Alpha Persei Moving Cluster because the star Alpha α Persei is at its center, and all the stars share a common proper motion across the sky.

And a galaxy

Now that you’ve become better trained in starhopping, I’m going to end by giving you a special treat. I said earlier that most galaxies are difficult for beginners to see, but one exception is the Andromeda Galaxy, quite close to Cassiopeia. Here’s how to find it. Look closely at the top three stars of Cassiopeia, Beta, Alpha, and Gamma. If you look closely, you’ll see that there’s a fourth star, Kappa κ Cassiopeiae forming a rather lopsided square with the three brighter stars. Use the line from Kappa to Alpha as your measuring stick, and follow the line from Kappa to Alpha two and a half lengths to the right. Through binoculars and your finder you should see a faint fuzzy patch. Through the telescope you will see a much larger fuzzy patch. Don’t expect to see its spiral arms or much else (unless you have very dark skies and a large telescope), but be aware that the light you are seeing is coming from more than two million light years away—that’s part of the magic of astronomy!

Geoff Gaherty
Geoff has been a life-long telescope addict, and is active in many areas of visual observation; he is a moderator of the Yahoo "Talking Telescopes" group.

[Top of Page]

The Saturn Nebula (NGC 7009) is an oval Mag 8 fuzzy patch hanging in space about 4,000 lightyears distant. Medium-sized scopes show a ring with "knobs" on either side.

M72, close by, is a small remote globular cluster, difficult to resolve. The open cluster M73 is a tiny triangular collection of stars, barely noticeable. However, the same field of view contains a lovely Lyra-like asterism.

The Mag 7 globular cluster M2 is about 40,000 lightyears away. Although among the brightest of globs in the sky, M2's core is so concentrated that, as an observational object, it ranks as one of the less compelling.

The Helix Nebula (C63/NGC 7293) is a tricky target. Although it is the largest visible planetary in the night sky (about half the apparent diameter of the full moon) it's quite dim. Dark skies are a must. A low power eyepiece in your telescope, with averted vision, may give you some hint of structure.

Finally, 103 lightyears distant is one of the sky's finest doubles, Zeta Aquarius.

Sean O'Dwyer, Starry Night® Times Editor

[Top of Page]

• Starhopping 101
  Geoff Gaherty's guide to finding interesting objects in the sky if you don’t have (or don't want to use) computer assistance.
     
• Best Objects for Fall Viewing
  Six easy-to-see objects, each one different from the last, each one a natural treasure chest.
     
• Constellation in Focus: Aquarius
  Tricky targets this month: two planetary nebulas, three star clusters, and one of the sky's best double-stars.

Seeing versus finding

There’s difference between finding the location of an object and actually seeing it. Many of the objects we amateur astronomers look at are too faint to be seen with the naked eye. Some are too faint to be visible in our scope’s finder. Some may be so faint as to be a challenge to see in the main telescope. Seeing can be difficult. Finding an object, on the other hand, involves pointing the telescope at exactly the spot in the sky where the object is located. This can be done with a computer, or manually using a technique called starhopping. It’s not necessary to be able to see an object to point at it with the telescope.

Many beginners make the mistake of looking for objects which are easy to find (because they are close to bright stars or familiar constellations) but which are very hard to see, because they are very faint. For example, many go hunting for the galaxy Messier 101 in Ursa Major because it is located close to two bright stars in the handle of the Big Dipper. Unfortunately, M101 is one of the most difficult objects in Messier’s catalog to see because it is large in size and very faint, so its dim light is spread over a large area. Unless you have very dark skies and a trained eye, you can be staring right at M101 and never see it! So it’s important, when you’re starting out, to go for objects which are both easy to find (located near bright stars or constellations) and also easy to see (bright clear objects, such as double stars and star clusters). Leave the dim galaxies (for the most part) until you have more experience.

Starhopping

Starhopping involves pointing your telescope using known guideposts in the sky: bright stars and constellations. This in turn requires some familiarity with the stars and their grouping. When you first look up into a starry sky, especially from a dark rural site, the view can be overwhelming. You wonder, “How will I ever be able to make sense of all these stars?” Learning your way around the starry sky is very much like learning your way around an unfamiliar city. It helps to have a map. It helps to have a familiar landmark or two to get your bearings. And it also helps to have a friend to show you the way. For a map, you have software programs like Starry Night® which will give you an overview of the territory. You may know a few “landmarks” in the sky to get you going, such as the Big Dipper, Orion, a bright planet, or the Moon. An astronomical friend is also very helpful in the early stages, someone who knows the stars a bit better than you do and can point out some landmarks. You may know such a person already, or you may need to find one by joining a local astronomy club. Although I’m not out there under the stars with you, I hope some of my suggestions here will also help you get started.

The first step is to print out a chart or two to take outside with you. Many of the charts you find in books or magazines are less than helpful for two reasons: they try to show all the sky, and they show it on too small a scale. I prefer to use charts which show only part of the sky, but which are on a large enough scale to approximate the actual spacing of the stars across the sky.

For example, here’s a chart from Starry Night® showing a section of sky roughly 90 degrees square, facing east at 8 pm on November 5:

Go out with this chart and face east. The top of the chart is overhead, the bottom is the horizon. The most obvious object in the eastern sky is Mars, glowing brightly about a third of the way from horizon to overhead. But our targets for tonight are farther away. As I said earlier, the Big Dipper is a poor starting place for deep sky hunting because it lacks bright objects. Let’s look instead at Cassiopeia, a constellation which lies almost directly opposite the Big Dipper in the northern sky. In this chart, it's about two thirds of the way from horizon to zenith, an obvious lopsided W shape, visible even under city skies. Once you’ve identified Cassiopeia, you have some landmarks which will let you point your telescope at a variety of interesting objects.

Here’s a more detailed chart of the Cassiopeia, made by zooming in with Starry Night®:

Besides your star chart, you will need a red flashlight to read it. You will also find it very helpful to have a pair of binoculars with a field of view similar to that of the finder scope on your telescope. I find 10x50 binoculars particularly useful for this. Binoculars let you practise the “hop” in a more natural way than the view through the telescope’s finder, which is usually upside down. After I’ve tried a “hop” a few times with binoculars, I’m ready to repeat it with the telescope finder.

Two double stars

Let’s start by tracking down a couple of double stars. Many beginners are unaware that many of the stars which appear single to our naked eyes are double or multiple in a telescope. They are great targets for beginners because they are easy to see as well as easy to locate.

The five bright stars in Cassiopeia which mark the W are named, from top to bottom in this view: Beta β, Alpha α, Gamma γ, Delta δ, and Epsilon ε. We can find our first double star, Eta η Cassiopeiae, by looking a little less than half way between stars Alpha α and Gamma γ. You can see it there in the chart below, marked by the Greek letter Eta η. Place the crosshairs in the finder of your telescope on that star, and when you look through the telescope you will see it is actually two stars: a bright yellow one and a fainter red one.

The second double star is a bit farther afield, but illustrates the principles of starhopping. Look at the two top stars of the W, Beta β and Alpha α. Use the distance between these two stars as your “measuring stick.” Extend the line from Beta to Alpha by two stick lengths to the lower right, which will take you to the star 51 Andromedae. Continue in the same direction about half the distance again, and you will reach a brighter star, Gamma γ Andromedae. This is our target: in the telescope it will appear as a double star, the two stars a bit closer than Eta η Cassiopeiae, and this time colored gold and blue.

Four star clusters

Now let's go after some deeper targets, some of the beautiful star clusters located in or near Cassiopeia. First take a close look at Delta δ Cassiopeia (second from the bottom in the W). In binoculars you will see a fairly bright star below and to the right of it, Chi χ Cassiopeiae. Use the line between Delta and Chi as the base of an equilateral triangle hanging below them, and put the crosshairs of the finder on the lower angle of this triangle. Through the telescope’s eyepiece you will see a compact little star cluster, number 103 in Messier’s catalog. Imagine a tall thin isosceles triangle on the opposite side of the same baseline, put your crosshairs there, and through the telescope you will see the star cluster NGC 457. It has two bright stars in it which many people see as eyes. Traditionally those are the eyes of an owl, the rest of the cluster forming the erect body of the owl with wings outstretched. But to our modern eyes, it looks rather like the character E.T. in the famous movie. So this cluster is called by some the Owl Cluster and by others the E.T. Cluster!

Let’s go hunting farther away. This time use the line joining Gamma and Delta Cassiopeia as your measuring stick and pointer. Go twice its length downward towards the horizon and you should see a fuzzy patch through your binoculars and finder. Through the telescope you will see the Double Cluster in Perseus, one of the wonders of the night sky in any telescope. If you keep going in the same direction towards the horizon you will encounter a line of three bright stars, the last of which is at the center of a little known star cluster, Melotte 20. The trouble with this cluster is that it is so close to us that its stars are spread wide across the sky, too wide to fit in most telescopes, so that they can only be viewed with binoculars or the naked eye. This is one of the star clusters closest to our Sun, also called the Alpha Persei Moving Cluster because the star Alpha α Persei is at its center, and all the stars share a common proper motion across the sky.

And a galaxy

Now that you’ve become better trained in starhopping, I’m going to end by giving you a special treat. I said earlier that most galaxies are difficult for beginners to see, but one exception is the Andromeda Galaxy, quite close to Cassiopeia. Here’s how to find it. Look closely at the top three stars of Cassiopeia, Beta, Alpha, and Gamma. If you look closely, you’ll see that there’s a fourth star, Kappa κ Cassiopeiae forming a rather lopsided square with the three brighter stars. Use the line from Kappa to Alpha as your measuring stick, and follow the line from Kappa to Alpha two and a half lengths to the right. Through binoculars and your finder you should see a faint fuzzy patch. Through the telescope you will see a much larger fuzzy patch. Don’t expect to see its spiral arms or much else (unless you have very dark skies and a large telescope), but be aware that the light you are seeing is coming from more than two million light years away—that’s part of the magic of astronomy!

Geoff Gaherty
Geoff has been a life-long telescope addict, and is active in many areas of visual observation; he is a moderator of the Yahoo "Talking Telescopes" group.

Tuesday, November 1
New moon at 8:25 PM

Thursday, November 3
Mercury and Venus are both at greatest eastern elongation

Monday, November 7
3AM, Mars is at opposition

Tuesday, November 8
First quarter moon

Tuesday, November 15
1 AM, a full moon passes 3° north of Mars

Thursday, November 17
Leonid meteor shower peaks before dawn

Wednesday, November 23
Last quarter moon

All times shown are U.S. Eastern Time.
   

Mars

Even after the its close approach on October 29th, the planet Mars will remain a dazzling sight. Throughout November it’s distinct peach-colored disc will be blatantly obvious, rising in the East in early evening. For a close-up view you’ll need a good telescope pushed to well over 100x magnification.

The Moon

The easiest space object to find, it is also the most fascinating. Even a 60mm telescope will show a terrain rich with craters, jagged mountains, and smooth basins. Sight along the “terminator,” the boundary between the light and dark portions. Shadows cast by crater walls and mountain peaks highlight those features. Full Moon is not a good time to observe see lunar detail because the Sun’s light is hitting the surface head-on, casting no shadows.

Albireo (Beta Cyngi)

This picturesque double star is located at the foot of the Northern Cross, or Cygnus. The two gravitationally bound stars create a striking color contrast in the telescope’s eyepiece: the brighter, 3rd-magnitude star is gold while the other, a 5th-magnitude sun, is blue. The colors will look even more pronounced if you defocus the stars slightly.

The Andromeda Galaxy (M31)

Look for this spiral galaxy in the eastern sky. The diffuse light from its billions of stars fills the eyepiece of any telescope. Use low power for the clearest image. You’ll see a starlike center and maybe even a dark dust lane. You are seeing the galaxy as it was 2.4 million years ago, which is how long the light has traveled to reach Earth!

Double Cluster

Near the “W” of Cassiopeia lies a pair of open star clusters called the Double Cluster. It’s a gorgeous sight in binoculars and small telescopes. The twin splashes of mostly white and blue-white stars span the width of two full Moons, so a wide-field instrument and low power will show them best. There are a few yellow-orange stars sprinkled among the masses. Can you spot them?

M15 Globular Cluster

You’ll find this tight ball of stars, the 15th entry in Charles Messier’s famous celestial catalog, just northwest of the bright star Enif in Pegasus. It’s one of the fall season’s finest globulars. In binoculars it will look like a fuzzy spot, but in a 4” or larger telescope you’ll start to resolve pinpoint stars around its edges. It’s hard to believe that so compact a cluster contains about 100,000 stars, but it does!

There’s plenty more where these came from! So get out and enjoy the fall’s celestial scenery.

Steve Peters

M72, close by, is a small remote globular cluster, difficult to resolve. The open cluster M73 is a tiny triangular collection of stars, barely noticeable. However, the same field of view contains a lovely Lyra-like asterism.

The Mag 7 globular cluster M2 is about 40,000 lightyears away. Although among the brightest of globs in the sky, M2's core is so concentrated that, as an observational object, it ranks as one of the less compelling.

The Helix Nebula (C63/NGC 7293) is a tricky target. Although it is the largest visible planetary in the night sky (about half the apparent diameter of the full moon) it's quite dim. Dark skies are a must. A low power eyepiece in your telescope, with averted vision, may give you some hint of structure.

Finally, 103 lightyears distant is one of the sky's finest doubles, Zeta Aquarius.

Sean O'Dwyer